The unrestricted use of fossil fuels should be phased out by 2100, if the world is to avoid dangerous climate change, a UN-backed expert panel says.

The Intergovernmental Panel on Climate Change says in a stark report that most of the world’s electricity can – and must – be produced from low-carbon sources by 2050. If not, the world faces “severe, pervasive and irreversible” damage.

The UN said inaction would cost “much more” than taking the necessary action.

“Science has spoken,”
Secretary-General Ban Ki-moon said. “There is no ambiguity in their message. Leaders must act. Time is not on our side.”
The IPCC’s Synthesis Report was published on Sunday in Copenhagen, after a week of intense debate between scientists and government officials.

“There is a myth that climate action will cost heavily,” said Mr Ban, “but inaction will cost much more. We have to first lower the temperature as you will to do with your children, that is what we are doing, that requires some massive, urgent and immediate action.”

The US Secretary of State, John Kerry, described the report as “another canary in the coal mine”.

“Those who choose to ignore or dispute the science so clearly laid out in this report do so at great risk for all of us and for our kids and grandkids,” Mr Kerry said in a statement.

The report says that reducing emissions is crucial if global warming is to be limited to 2C – a target acknowledged in 2009 as the threshold of dangerous climate change.

For electricity production, this would mean a rapid move away from coal and into renewables and other low carbon forms, including nuclear.

In the longer term the report states “fossil fuel power generation without CCS is phased out almost entirely by 2100”.

CCS refers to “carbon capture and storage” technology, which could help limit emissions but is proving slow to develop.
Three previous reports from the IPCC, issued over the past 13 months, have outlined the causes, the impacts and the potential solutions to climate change.